The Analysis of Ecological Structures and Functions of Pelagic Fishes in Bandon Bay, Suratthani Province

Abstract

The coastal ecosystem of Bandon bay is high productive ecosystem with high abundance and
diversity of aquatic animals. Hence this bay has been overexploited and several sources of pollution may
cause to decline of fishery production. It might be affect to ecosystem structure and functions. This study
aimed to investigate trophic structures and ecosystem functions of pelagic fish. ECOPATH model was
used to estimate the important biological parameters and ecological importance of pelagic fishes. The
model simulation was based on the data collected from artisarnal fisheries of costal fisheries areas of the

Bandon Bay. There were 14 functional groups. The average values of Ecotrophic Efficiency (EE) in the
model were high (>0.6) for the most groups of high trophic level. The trophic levels were varied from 1.0
for primary producers and detritus to about 3.44 for pelagic piscivorous fishes (Eleutheronema tetradactylum).
Gross efficiency of the fishery was indicated intensive efforts in the area (0.01). Phytophagous fish played
an important role in linking between the lower trophic organisms and top predators. Increasing of
phytoplankton biomass would benefit any group. The mixed trophic impacts indicated the importance of
bottom up influence of phytoplankton abundance variations on the food web of the Bandon Bay ecosystem.